<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
</head>
<body>
<div>
    <form id="myForm" method="post" th:action="@{/trustclientdata/wrong}">

        <select id="countryId" name="countryId">
            <option value="0">Select country</option>
            <option th:each="country : ${countries}" th:text="${country.name}" th:value="${country.id}"></option>
        </select>

        <button th:text="Register" type="submit"/>
    </form>
</div>
</body>